Evaluation of the intra- and inter-observer reproducibility of a method for studying three- dimensional knee kinematics

A major difficulty in evaluating in-vivo knee joint kinematics during walking is the artifacts created by movement of the skin and soft tissue relative to the underlying bones. An attachment system called exoskeleton has been proposed to remedy this problem; its precision is known as well as the repeatability of its calibration method. The objective of this study was to verify the intraand inter-observer repeatability of this system. Also, as the installation is more complex than that of other systems, the effect of the observers’ experience was investigated. Results show a mean repeatability below 1.3° in the intraand inter-observer settings. Observer experience had no effect on the results although a slight learning curve may exist for novice observers. Keywords-component; three-dimensional kinematics, knee kinematics, anatomical frames, functional method, validation, repeatability